Cambridge is probably best known for King’s College, Isaac Newton, and being the home of a world famous university. But now the city is at the forefront of growing movement across Britain to preserve another great institution: the pub.

The city has lost 20 pubs recently, prompting an outcry from residents fed up with seeing their local watering holes closed down or converted into something else, such as apartments or restaurants. Now pub owners will have to prove their pubs aren’t viable before getting approval for any redevelopment.

It’s all part of a national effort to reverse the sudden and steep decline of pubs across Britain. The number of pubs has been falling for decades, but the drop picked up steam in the few years, after nearly 8,000 establishments were lost from 2006 to 2011. A kind of call to arms has gone out to stem the tide.

“People don’t like it when their last remaining neighbourhood pub closes and we get campaigns to save them and so on,” said Cambridge city councillor Tim Ward. “So we’ve responded to that public demand and put some planning policy in place.”

Cambridge’s lead has been picked up by the London borough of Kensington and Chelsea, which plans to introduce a similar requirement to demonstrate a lack of viability. An online petition demanding that the government help pubs by cutting beer taxes has attracted more than 100,000 signatures, and this week British MPs will debate in parliament about what more can be done to save pubs.

The humble public house has been a part of Britain’s social fabric for hundreds of years, with some historians dating the origins of pubs to Roman times. And there are still plenty around – roughly 50,000 at last count. But that’s down from 69,000 in 1980 and 58,200 in 2006, according to the British Beer and Pub Association. And it is likely even lower, since the association has yet to tally the total for 2012. By some estimates Britain is losing 18 pubs a week, up from 12 a week last year.

“It has been very tough,” says Dawn Hopkins, who runs two pubs in Norwich with her husband Kevin. The couple have done just about everything to keep their venues afloat. They’ve cut staff, changed the product line and even sold the family home to help cover costs. “There are a lot of things against us and not much going for us,” she says. She adds that she can count at least three pubs that have closed within walking distance of one of their establishments, called Ketts Tavern.

She and others point to a myriad of reasons for the crisis. Many blame a beer duty imposed by the government in 2008, driving up the price of a pint just before the recession took hold. Others point fingers at giant supermarkets such as Tesco and Sainsbury’s, which can sell alcohol at far lower prices than pubs and now account for about 70 per cent of all booze sales. And then there’s the impact of smoking bans, similar to those at bars and restaurants across Canada, which some say has kept customers away.

But changing consumer preferences are an even bigger factor. Many pubs, even those in villages, can only survive if they become almost like bistros, offering extensive food menus and wine lists. Britons are drinking less in general, and drinking less beer in particular. The number of coffee shops is soaring, along with a multitude of restaurants offering far more variety than the pints and crisps on offer at most pubs.

Big pub owners have taken note. Punch Taverns, one of the largest pub operators in Britain, is cutting nearly 3,000 drink-only pubs over the next few years and concentrating only on those that operate more like restaurants. The future of the pub industry “will favour the larger food-led destination pubs and so a disproportionate number of the closures will be from smaller predominantly drinks-led pubs,” Punch chief executive Roger Whiteside said in the company’s latest annual report.

In Cambridge, pubs have taken their cue as well and started converting into restaurants or student apartments, which are more profitable. Two more have recently announced plans to do the same, prompting the first direct challenge to the new planning rules. Mr. Ward said council will take a hard look at the owners’ requests and the reasons why they no longer want to operate as pubs.

“You have to show that it’s not popular, it’s not profitable and it can’t be made profitable,” he said. “So just running it into the ground, by putting in a bad manager and being rude to all your customers, isn’t good enough.”